Generally, the weapon that can reach out and effectively touch you from a longer range has the advantage. So yes, pole arms do possess advantages over swords, unless the swordsman gets inside the pole arms range. We train in medieval dagger fighting, and it's amazing how simply stepping a foot closer towards your opponent often renders his blade less than effective, if not downright ineffective.
As far as the katana goes, Japan could produce small amounts of very high quality steel. However, she couldn't mass produce it. Remember, she's an island nation with poor natural resources, an issue which would plague her in 20th Century warfare. Most Japanese weapons were of serviceable though hardly high quality steel. The incessant hammering and folding was necessary to eliminate carbon and slag to a manageable level, something that wasn't nearly as critical in European steels, some (though certainly not all) of which were actually crucible steels as far back as the Viking Age. Indeed, what crucible steel the Europeans couldn't make themselves, they typically imported from Persia and India all through the Middle Ages. I'm not saying that katanas would instantly shatter, but that was a concern, as the almost ritualistic care that katanas received indicates. Indeed, the very way they were wielded was arguably meant to reduce damage. The very triangular thick back of the blade likewise imparted stability and stiffness to what may have been lukewarm quality metal.
Why were they curved? Very likely as a result of the quenching process, the intense heat transfer imparting the curve via dissimilar cooling. Deliberately making a curved sword adapted the smith's task to the usually poorer quality steel which had a natural tendency to curve, so why fight Mother Nature? Adapt to her whims. This created a superbly light, fast sword but one with certain inherent limitations.
None of this is meant to belittle the katana. However, an almost cultish myth has grown up which states that the katana was simply the best sword ever made. Nope, not hardly. It was an immensely capable cutter of fabric, flesh and light cloth armors. It could NOT cut through steel armors at all, as a general rule. However, the average European longsword could cut the exact same materials in an unsharpened state. Trust me, I've tried it. An unsharpened longsword can easily cut, and in tests have cut right through thick long bones. Part of this is the swordsman's skill, yes, but a large part is the blade geometry. Cruciform swords simply possess more leverage and "blade presence," in general, than katanas.
As far as thrusting goes, there is no comparison. The katana's curved blade makes accurate thrusting difficult. It can thrust, just not particularly well. The longsword's tip, however, is deadly. Check out an Oakeshott Type XVII and it's intended use and you'll see what I mean. While rare, there are anecdotal claims of longswords thrusting through actual plate armor. I suspect this was defective armor or the result of some freak occurrence as plate could generally not be thrusted through by swords, but it apparently did happen (RARELY!). I doubt a katana could do that, and the few times the katana met Spanish or Portuguese plate as well as longswords, well, the samurai didn't come off terribly well.
The bottom line was that the longsword was a "reach out and touch you," weapon that in the hands of a trained user (think Talhoffer, Lichtenauer, Fiori) was just as nimble as the katana. It could thrust better, and weighed maybe an ounce or two more. Plus, it had supremely better hand defenses,and could be half sworded - try that with a katana. Finally, every part of the longsword is a fighting surface, including the crossguard and the pommel. Every wonder where the word, "pummel," comes from? Some believe it descended from the pommel, which was a striking and bashing weapon of it's own. I've taken a few pommel strikes in practice and even a quarter speed or less, they WILL be flt. Katanas can't do pommel strikes since they don't possess pommels.
Decker, that looks like a great club! I'm going to my first competition in November in our beginner's group. I"ll likely get my head handed to me but I'm going to try!
Bob